Screw and nut



FIG. 1 discloses a bottom perspective view of a nut showing the nut portion my new design;

FIG. 2 discloses an elevational view thereof;

FIG. 3 discloses a bottom plan view thereof; and,

FIG. 4 discloses a top plan view thereof. 

CLAIM The ornamental design for a screw and nut, as shown and described. 